The invention provides a pressure swing adsorption process for the separation of a pressurized feed gas supply containing one or more strongly adsorbable components and at least one less strongly adsorbable product gas in a multiple bed system. The feed gas is supplied to a feed end of an adsorbent bed containing solid adsorbent material(s), which preferentially adsorb the more strongly adsorbable component(s) and withdrawing the least strongly adsorbable product component from an exit end of the adsorbent bed. This is performed in PSA cycle(s) comprised of steps in which the continuous feed gas sequentially, and co-currently flows through each of the adsorber beds to produce gas product using continuous feed gas, pressurization steps, pressure equalization step(s), blowdown step(s), and purge step(s).
The product gas of the process is preferably hydrogen although the process can be extended to other separation processes such as helium purification, natural gas upgrading, CO2 production from synthesis gas or other source containing CO2 in the supply feed or in other PSA processes for coproduction of H2 and CO2. One of the novel features of the present invention is the introduction of new and advanced cycle to PSA systems having twelve to sixteen beds. The twelve be PSA cycle has four equalization steps, while four beds are in parallel feed to achieve enhanced H2 recovery. This cycle can be further modified and operate the PSA system in a turndown mode with a relatively small reduction in throughput, thereby allowing the PSA system to operate with as few as five beds. In addition, the new PSA process cycles take advantage of the sequential refluxing protocol to improve the regeneration steps, and the overall performance of the PSA system.
Another novel feature of the invention is the layered adsorbent, which can be utilized in the beds. These layered configurations of carbon and/or zeolite components differ from another layer of similar adsorbent material in particle size. These layered configurations of the bed materials combined and the PSA cycles provide a synergistic effect with an overall improvement in hydrogen recovery and throughput of 1-2% over conventional PSA cycles.
In a first exemplary embodiment of the invention, pressure swing adsorption process for separating a pressurized supply feed gas is provided. The feed gas containing one or more strongly adsorbable component is separated from at least one less strongly adsorbable product gas component in a twelve bed adsorbent system to produce a continuous stream of product gas enriched in the less strongly adsorbable component and a continuous stream of offgas that is enriched in strongly adsorbable components, wherein the process cycle has twenty-four steps including four bed-to-bed equalizations steps, while four of the beds are in production.
In other exemplary embodiments of the invention, the pressure swing adsorption system is in turndown mode with only nine, eight seven, six or five beds online and in production. In these embodiments, the process cycles are described herein.
In yet an alternative exemplary embodiment of the invention, the twelve bed PSA process cycle is modified to have twenty-four steps including five bed-to-bed equalizations steps, while three of the beds are in production.
In further exemplary embodiments of the invention, the PSA system can be scaled up to include fourteen or sixteen beds in the PSA system/skid/train. Novel cycles are provided where the fourteen bed PSA cycles have twenty-eight steps, including five bed-to-bed equalizations, and five beds are in production. The sixteen bed PSA cycle has thirty-two steps, including six bed-to-bed equalization steps, while six beds are in production.